Parasitic diseases in humans and animals cause substantial suffering and economic losses throughout the world. Thus, control of parasitic infections remains an important global endeavor. The causative organisms include helminths, such as nematodes, cestodes, and trematodes. These organisms can infect, for example, the stomach, intestinal tract, lymphatic system, tissues, liver, lungs, heart, and brain.
There are many known drugs (or “anthelmintic agents”) available to treat various anthelminitc infections. These reportedly include, for example, various avermectins (e.g., ivermectin, selamectin, doramectin, abamectin, and eprinomectin); milbemycins (moxidectin and milbemycin oxime); pro-benzimidazoles (e.g., febantel, netobimin, and thiophanate); thiazole benzimidazole derivatives (e.g., thiabendazole and cambendazole); carbamate benzimidazole derivatives (e.g., fenbendazole, albendazole (oxide), mebendazole, oxfendazole, parbendazole, oxibendazole, flubendazole, and triclabendazole); imidazothiazoles (e.g., levamisole and tetramisole); tetrahydropyrimidine (morantel and pyrantel), organophosphates (e.g., trichlorphon, haloxon, dichlorvos, and naphthalophos); salicylanilides (e.g., closantel, oxyclozanide, rafoxanide, and niclosamide); nitrophenolic compounds (e.g., nitroxynil and nitroscanate); benzoenedisulphonamides (e.g., clorsulon); pyrazinaisoquinoline (e.g., praziquantel and epsiprantel); heterocyclic compounds (e.g., piperazine, diethylcarbamazine, dichlorophen, and phenothiazine); arsenicals (e.g., thiacetarsamide, melorsamine, and arsenamide); cyclooctadepsipeptides (e.g., emodepside); and paraherquamides. See, e.g., McKellar, Q. A., et al., “Veterinary anthelmintics: old and new,” Review: Trends in Parasitology, 20(10), 456-61 (October 2004).
While many parasitic infections can be treated with known drugs, evolutionary development of resistance by the parasites can render such drugs obsolete over time. See, e.g., Jabbar, A., et al., “Anthelmintic resistance: the state of play revisited,” Life Sciences, 79, 2413-31 (2006). In addition, known drugs may have other deficiencies, such as limited spectrum of activity and the need for repeated treatments. Thus, there still exists a need for new anthelmintic agents to ensure safe, effective, and convenient treatment of a wide range of endoparasitic infections over a long period of time. The following disclosure describes a group of such agents, as well as methods for making and using them.